With increasing efficiencies and capabilities in solid-state lighting technology, solid-state light emitting devices such as LEDs are in a process of replacing traditional incandescent and/or fluorescent light bulbs for general illumination. LEDs typically have higher light conversion efficiencies and have longer lifetime than conventional light sources. With continuing development of LEDs, LEDs will have higher light conversion efficiencies and less energy consumption. For LEDs to be accepted to general lighting applications, it not only provides high energy conversion capability, but also adopts existing lighting standards and infrastructure. An advantage of using the LEDs for general illumination is that they are more energy efficient, compact, and reliable in comparison with traditional lighting fixtures such as incandescent or fluorescent light bulbs or lamps.
A drawback, however, associated with a typical LED lamp is that it usually delivers a directional light, also known as light forward or forward light cone. A reason that an LED lamp gives off light in one direction is that an LED lighting apparatus is a forward illuminating light source. However, under luminous flux measurement (“LM”) 79 specifications, a typical lighting fixture such as incandescent lamps is required to deliver omnidirectional light and/or illumination.